A bright red male Spinecheek Anemonefish (Premnas biaculeatus) swims above his host sea anemone on the northern reefs off Great Barrier Reef north of Cairns in Queensland, Australia.
The female of this species is larger, and generally display a much muted red coloration than the male. They are also tremendously territorial and their aggressive displays are well worth observing.
The smaller male, as can be seen here, are much brighter and much smaller than the large female.